textproduct: Quad Cities

KEY MESSAGES

- Hot and humid conditions are expected today with heat indices up to 110 degrees. An Extreme Heat Warning and Heat Advisory are in effect this afternoon. While hot and humid conditions are expected to continue Monday, lower confidence due to morning storm potential has kept an Extreme Heat Watch in place area-wide.

- Thunderstorms, including some strong to severe, are possible late tonight through Monday morning. SPC has a Slight (level 2 of 5) risk of severe thunderstorms is in effect for late tonight.

SHORT TERM /THROUGH MONDAY/

Issued at 235 AM CDT Sun Jul 26 2026

Radar imagery early this morning shows areas of decaying convection upstream across northern Iowa, southern Minnesota, and eastern South Dakota. This will move into eastern Iowa over the next several hours, bringing low chances (10-30%) for rain through the early morning. How long these clouds linger into mid-morning could help limit temperatures later today, though it is likely (60-80%) that low clouds will clear out and allow for diurnal heating. This will support another day of increasing heat and humidity, with temperatures rising into the low to mid 90s and heat indices from 100 to near 110 degrees. A Heat Advisory for northwest Illinois and an Extreme Heat Warning for the remainder of the area remain in effect for this afternoon.

As we look towards Sunday night, the question turns from heat headlines to storm potential as a shortwave moves through late Sunday night into Monday morning. While a combination of capping and limited forcing will keep any convection limited to non-existent during the day in our area, stronger forcing upstream will allow for convection to develop upstream. Any storms that move into the area will be able to take advantage of a favorable environment with 30-45 kts of shear, high lapse rates, and seasonable CAPE of 3000-4000 J/kg to become strong to severe. The primary threat with any storms would be wind, due to to seasonably strong winds aloft. As for where storms would occur, the most likely is in northwest Illinois, as the instability gradient will be draped across northern Illinois. However, while much of the guidance keeps this over our northwest IL counties, a few of the models shift it further eastward, leading to the storms also shifting eastward.

The uncertainty in where storms could be has led to some uncertainty in heat headlines for Monday. Heat and humidity are once again likely (60-80%), but the degree of how hot it will be is in question. There are two potential avenues for how this could play out. First, if there are limited storms overnight through Monday morning, temperatures will be similar to today's forecast highs and heat indices, if not a degree or two warmer. This scenario would favor an Extreme Heat Warning. However, if storm coverage is higher and convective debris lingers through Monday morning, highs could be limited to the upper 80s and low 90s, warranting a Heat Advisory instead. This uncertainty in storm coverage and evolution Sunday night has prompted the continuation of the Extreme Heat Watch at this time.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Issued at 235 AM CDT Sun Jul 26 2026

Monday evening, a cold front sweeping through will provide some reprieve from the humidity, though hot temperatures are expected to continue through the middle of the week as we sit on the edge of a ridge stretched across the Intermountain West. By Friday, this ridge will retrograde westward, allowing for the ring of fire to be over us once more. There still remains a signal for a shortwave to move through the flow Friday, suggesting that this may be our next chance for some rainfall and cooler temperatures.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 620 AM CDT Sun Jul 26 2026

A stubborn area of low stratus will result in periods of IFR/LIFR early this morning. Improvement is likely by mid/late morning as ceilings increase and the cloud deck begins to break up. MVFR/IFR fog is also anticipated early this morning with visibilities as low as 1-4SM. An isolated shower or storm could develop today with slightly higher chances for some storm activity late tonight (10-30%); did not include thunder in the TAFs with this update due to low confidence on coverage and impacts at the terminals.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Extreme Heat Warning from 11 AM this morning to 9 PM CDT this evening for IAZ040>042-051>054-063>068-076>078-087>089- 098-099. Extreme Heat Watch from this evening through Monday evening for IAZ040>042-051>054-063>068-076>078-087>089-098-099. IL...Extreme Heat Warning from 11 AM this morning to 9 PM CDT this evening for ILZ009-015>018-024>026-034-035. Extreme Heat Watch from this evening through Monday evening for ILZ001-002-007-009-015>018-024>026-034-035. Heat Advisory from 11 AM this morning to 9 PM CDT this evening for ILZ001-002-007. MO...Extreme Heat Warning from 11 AM this morning to 9 PM CDT this evening for MOZ009-010. Extreme Heat Watch from this evening through Monday evening for MOZ009-010.